Railway car truck bolster stabilizer



` K. M. HAMILTON 2,661,703 RAILWAY CAR TRUCK BoLsTER STABILIZER S sheets-snaai 1 Dec. 8, 1953 Filed June A26, 194e INVENTOR. fz/Z MHQUZLZLO BY Dec. 8, 1953 K. M. HAMILTON 2,661,703

RAILWAY CAR TRUCK BoLsTER STABILIZER Filed June 26, 1946 3 Sheets-Sheet 2 Dec. 8, 1953 K. M. HAMILTON RAILWAY CAR TRUCK BOLSTER STABILIZER 5 Sheets-Sheel'I 5 Filed June 26, 1946 Patented Dec. 8, 1953 UNITED STATES PATENT OFFICE RAILWAY can TRUCK BoLs'rER STABILIZER My invention relates to car truck bolster stabilizing means for controlling excessive oscillation of the bolster relative to the truck frame and involving spring means for maintaining a frictional relation between the stabilizing means, carried by the bolster, and the truck frame independently of the bolster spring suspension or bolster supporting springs.

The invention more specifically stated involves providing the bolster adjacent its ends with suitn able pockets having openings through the sides and bottom of the bolster and the pockets provided with transversely slidablefriction shoes or blocks adapted to effect frictional contact with the bolster top wall and the adjacent portions of the truck frame through the action of a single wedge element or block which in turn is yieldingly forced and maintained in wedging position through the action of suitable spring means which, together with the friction blocks and wedge block, are all mounted within the bolster and independent of any external elements.

My invention has for its object the provision of bolster stabilizing means of simple construction and arrangement adapted for application to constructions at present in use and to a standard A. A. R. bolster and truck frame without necessitating change in `height and width of the standard equipment and which permits the use of the standard bolster spring grouping and hence enables the use of a comparatively small spring plate and narrower width of side frame spring seat, or standard length of spring plank, if the latter is used.

Another object of the invention is the provision of a `bolster stabilizer designed to produce a constant frictional condition or relation with the adjacent portions of the truck frame, with a light or loaded car; and in which the friction producing condition is mechanically obtained without prior friction spring compression in the bolsters before assembly into a side frame or without manually compressing the friction springs after the holsters are assembled in the side frames; a construction wherein the friction elements exert no variable pressure during the vertical or up and down movements of the bolster.

A further object of my invention is simplicity, in design, in application and in maintenance and in initial cost, with the various parts having comparatively large and substantially at frictional contacting surfaces ensuring continuous operation as a result of the use of a single vertically operating coil spring in each bolster end pocket which ensures constant friction shoe pressure under a light or loaded car at all bolster positions; a constructionl wherein the contained spring of the stabilizer may be easily regulated by the introduction of suitable shims either at the top or at the bottom oi the enclosed friction producing spring to compensate for wear of the shoes or adjacent elements, without the necessity of removal of the bolster and its contained stabilizing elements.

The objects and advantages of the invention will be readily comprehended from the following detailed description of the accompanying drawings wherein:

Figure 1 is a plan view of one end of a truck bolster with the stabilizing means receiving pocket shown in dotted lines and the load springs shown in dotted and full lines while the stabiliz ing means are omitted.

Figure 2 is a side elevation of the bolster end shown in Figure 1.

Figure 3 is an outside elevation of the intermediate or Window opening portion of a truck side frame with the inserted end of the bolster showing the inserted stabilizing means in dotted lines, and the bolster supporting springs in elevation.

Figure 4 is a cross sectional View at the end of the bolster and of the contained stabilizing means in operative position, taken on line 4--4 of Figure 5, with a portion of the side frame and supporting springs shown in side elevation.

Figure 5 is a sectional View taken on the line 5-5 of Figure 4, showing the operative position of the elements under a light or loaded car.

Figures 6 and '7 are sectional views taken on the same lines as Figures 4 and 5, but showing the bolster in its extreme raised or jacked up position for application or removal of the bolster supporting springs, with thestabilizing elements in contracted or non-friction yapplying position.

Figure 8 is a top plan view of my improved wedge element.

Figure 9 is a side elevation of the wedge ele ment as viewed from a side of Figure 8.

Figure 10 is a top plan view of one of the friction elements or blocks.

Figure ll is a side elevation of the same.-

Figures 12 and 13 are views similar to Figures l0 and 11 showing the companion friction block; Figures 8, l0 and 12 in reality constituting what may be termed an exploded view of the stabilizing means with the respective elements positioned to be brought together in assembled operative position. y

Figure 14 is a bottom plan view of the friction elements or blocks (both friction blocks being similar).

Figure l5 shows the spring holding cup in side elevation.

Figure 16 is a side elevation of the cup as viewed at right angles to Figure 15.

Figure 1'7 is a bottom plan View of the cup.

Figure 18;,shows Lthe friction*-springy infposition to enterthe "wedge block, Figure. 9, rand-.i the spring cup as shown in Figure l5.

Figure 19 is an elevation of a portion of one end of the bolster with the stabilizing -means shown in dotted lines and in release'or nonfriction applying position.

In the particular eXemplifieation.mysinvention is shown applied to a standard truss type of railroad car truck frame 25, the`v intermediate or Window-opening portion of which isshownfat 25a with the window-columns 25, 25 which are ...preferably ,provided with wear. plates. as at 21,

. The .Window-opening '25a is intended to receive A`-oneend -of the truck rbolsterzZB, provided .with vthe fusual guide lugsor ribs-:.291asshownfin Figure ,1*,radaptedto overlapfthe columns 25 of .theside frame. The structure.- thus far describedis` the ...standard A: A. R; type of.A truck frame and bolster -arrangement In order to receive my improvedsstabilizing .305-3e-asshownwindotted lines in Figure l randf -.infu11lines Figures 5 and 'l to provide a plane Arfourww'alled :chamber-for. :pocket therebetween which isV openat opposite :sides of :the bolster and with a central bottom opening `at-Zr Athe Walls preferably oi-set or recessed .at-3|-, 3I to -receive the-.outer ends ore-headsl off the frictionelements 32;'32; the laterally extendedfends-orheads-ebefzingrshown at 33; see' Figures i 10.1 and'l2;which fprovi'dew-idef bearing or`friction surfaceszfor" engaging :the Wear z plates 121'; f 2. fAsf'bothriction blocks 32, 32 are identical a description of one 'will zsuflee.l .JThese I blocks f or 'shoes-Lwhich are .preft erably `hollowreetangular` castings'with' flat tops `and bottoms'and outer plane endse-at'theirinnera "ends are reach #formed withY arr `upwardly vandin- Wardly inclining .surfaceV 34 fand may-'befsomeffwhat inset i intermediatev E oppositel #sides at` :.the

ftopiofftthe block,- as shown at 5:35;v While the bottom of lthev block' intermediate. itsvsides-:may tbe.

Iprovided with rarr-extensionV or lug-T535, preferably of'round-contour; for a-purposemhei'einafter to abe 1 described fthe -bottom fof' the blockl-b'eing shown'provided with a substantially semi-circular '-socketfBT-in the sideiotthe blockl for apurposes @hereinafter described.

"These friction blocks T32, 32 are insertedl 'from each end of the pocket in the bolster-*(two-blocks Yfor eachpocket) andare. intended to `cooperate With an intermediate Wedge element"orfblock'311:4 .fof rectangular 'co'ngurationas shown vitt-Figure 8 and consisting preferablyofVv ahollowca'sting disposedtransversely ofrthe' bolster with itsslopsing or incliningv ends y39,'-39v matchingaand: in-

:tended'to cooperate With the sloping surfacesf34,

34"ofpthe adjacent friction` blocks32; 3'2. The wedge block'or elementf38 at its bottom mayvhave depending `lips 140,- 4t Which rest onrthe floor or'fbottomof thef bolster-f28^when in lowered or non-Wedging position. As is apparent-,"when the with a` substantially flattop to receive" the upper end of a friction spring 4| positioned as shown Bazin Figure 18, While the lower end of the spring `.134.seatswin a spring holding cup 2 which is ..-,adapted to fit into the opening 28?- and flush with the bottom of the bolster all as shown in Figures sand i5.

The cup`42is shown provided with a at bottom andthe side Walls at opposite sides proyided'lwith upstandingguide arms 43, 43 which are slightly off-set outwardly, as more clearly .shownt in .Figure 17T; andV are intended; toi fit into the laterally oi-setcporticnsb inthe opening .28A in the bolster-bottom',- shown in -dotted .lines ,in-Figure l, to prevent rotationof the spring'cup. The cup-42 also is provided4 withupstanding .ar-ms 44 at diametrically ioppositefpoints Zintermediate fthe-pair of arms :63; andztliese arms -llli :maybe each provided with a :verticallylarranged' slot 45 intendedl to'receivezthe extensionfiorslugwS of the adjacent frictionblockc'as shownin Figures 3, 4 and 6; the Alugsx-Sifoi' the two-.oppositely yarranged friction. blocksare'. intended v'to hold the cup from droppingout zof the bolster icpenmg.

The outerend Waller. partition 3Q inthe bolster atthe bottom'of the bolster..iszshown'provided With apair of .openings ated which Aare adapted 'to align withy the-:sockets Y3'! vinY they lower aparts of the friction -rblocksz32g .32; during` vassern'blyiof the stabilizing means; .for "the purpose of .receiving a small'- .Wood dowel tor.v any:` soft/` sheaable materiaL` lWherebytlie;respective frictionelements will bef temporarily flield" in fretracted; position within: the @bolster-pockets .and .thus 'allow' the 1 ends of ithe bolster: toi-beY inserted'in proper posiitionx-betweenthecolumns v26; .i126y off'the truck frame.

Myimproved'stabilizingmeans is assembled'` by .first.finserting;y the'fwedge: element for block :'38

n .throughxonerendiofethef bolster-pocket 'and placing Vit Yacross "the bottom -iopeningi 28a; :then in- -fserting cup :42' withf friction: spring 4 i through the .bottom opening-128a :with .the upper end of the spring entering into the ihollow'wedge block 33; Ythe .cup ibeing l.pressed 'upisufliciently to .'bring :the upper endsof': the slots"45f45 in arms/.44,

144; aishort distance, above the bottomiof` the fpocket :andi:theacupftemporarily .held in this yposition. The frictionblocks '32,'- 32 :are thenginfserted througlitl'reir :respective ends of` the pocket, YWith r theirY sloping iisurfaces 34, 34: in .contact iwith'the incliningfsrfaces:39; 3Sof they Wedge tion blocks--beingi"thentemporarily heldin position'entirely within theA bolster-pocketl bysinserting a soft shearable element or Wood dowelin .theregistering holes inthe outer pocket Wall and r-70 f bottoms of the'frictioniblocks. The bolster, with the assembled stabilizing means, may then -be rinserted in place in Athe*trli'czlrfrarurie, as thelugs on Vthe retracted friction blocks will vhold the :spring-cup from: dropping .out of the'bolster-bot- A`tomfopening. YTliezmain portionfof the-wedge 5 block 38 is held above the floor of the bolsterpocket by the depending lips ct at the ends, thus providing passage for the extensions or lugs 3B of the friction blocks.

The bolsters positioned in the side frames are then jacked up for the placing of the load springs 41 of standard or other grouping. Bolsters with contained stabilizing parts mounted in truck frames are then brought from an inoperative to an operative position by placing a car body on a pair of truck bolsters. This added weight moves the bolsters downward compressing the load or bolster supporting springs to their light car operating height. Spring cup 42 with contained spring 4i contacting a part of these load springs will be urged through bolster bottom floor opening 28a to its operating position flush with the bolster bottom floor. Spring 4l will be positioned at its proper operating height and the upper end of this spring contacting the wedge member will urge this member to its operating position, the wedge member contacting the angular inner faces of the friction shoes, moves these members upwardly and outwardly into bolster and side frame contact, shearable friction shoe retaining means if left in holes 55, 46 would be sheared off by the movement of the friction shoes.

Should it be desired at any time to increase friction spring pressure to compensate for shoe face wear or for other causes, a shim inserted at either the upper or lower end of the friction spring can simply and easily be applied.

Inasmuch as load springs 4l contact both the spring cup 42 and the bolster bottom floor 28d any movement of the cup 42 beyond a flush bolster position-would be mechanically impossible.

The exempliflcation disclosed in the drawings is believed to be a simple embodiment of the invention but structural modications may be possible without, however, departing from the spirit of my invention as dened in the appended claims.

What I claim is:

1. In a railway car truck bolster stabilizer, the combination of a truck side frame with a bolster receiving opening having side columns, bolster supporting springs arranged in the bottom of sald opening, a bolster resting on said supporting springs provided with transversely disposed four plane walled pockets at the ends and open` at the sides of the bolster with a central opening in each pocket through the bottom of the bolster; a pair of friction blocks having upwardly sloping inner ends, slidable in the ends of each pocket and adapted to frictionally engage the truck frame columns; a hollow wedge block arranged in each pocket between the inner ends of the friction blocks, the adjacent portions of the fricvtion blocks and said wedge block having matching sloping surfaces in contact with each other whereby the friction blocks are forced through the open ends of the pocket when the wedge block moves upwardly in the pocket; a vertically extending coil spring and a spring holding cup insertible through said bolster-bottom opening with the upper end of the spring bearing against the inner surface of the top of the wedge block and exerting constant upward pressure on the wedge block, the bottom of said cup being adapted to extend flush with the bolster-bottom and to be so maintained by the bolster supporting springs without affecting the pressure of said cup spring.

2. In a railway car truck bolster stabilizer, a

truck side frame with a bolster end receiving opening, a bolster provided with a four walled pocket in each end and with self contained stabilizing means in each pocket consisting of laterally movable friction blocks, a vertically movable hollow wedge block between the inner ends of the friction blocks, the inner ends of the friction blocks and adjacent ends of the wedge block having matching sloping faces, a spring holding cup beneath the wedge block, a vertically disposed coil spring seated in said cup with its upper end arranged in the wedge block and exerting upward pressure on said wedge block, the inner ends of the friction blocks and said spring holding cup having interengaging surfaces whereby the cup is held in the bolster when the friction blocks are out of contact with the side frame.

3. In a railway car truck bolster stabilizer, the combination of a truck side frame with a bolster receiving opening having bolster supporting springs in the bottom, a bolster whose end extends into said frame opening and rests on said supporting spring provided with an opening in its bottom, openings in the sides and self contained stabilizing means in each end involving friction blocks laterally movable through said side openings, a hollow vertically movable wedge block open at the bottom, a coil spring holding rigid member with upstanding portions arranged in the bolster bottom opening beneath the open bottom of the wedge block and supported in place by said supporting springs, a vertically disposed coil spring seated on said rigid member with the upper end of the coil spring extending into the hollow wedge block and exerting upward pressure on the wedge block to cause the latter to move upward and thereby force the friction blocks into frictional engagement with the side frame, and means carried by said friction blocks and arranged in operative engagement with upstanding portions of said rigid member whereby the rigid member is held suspended in the bolster bottom opening when the bolster is free of the supporting springs and thus permit the wedge block spring to expand.

4. In a railway car truck bolster stabilizer, the combination of truck side frames with bolster end receiving openings and bolster supporting springs; with a bolster, adapted to extend into said frame openings, provided with transversely disposed pockets at the ends and open at the sides and bottom of the bolster, each pocket containing a pair of friction blocks transversely slidable in a pocket of the bolster and adapted to effect frictional engagement with the side frame, a vertically movable hollow wedge block between the friction blocks and in pressure exerting engagement with the inner ends lthereof, a coil spring arranged in each pocket and disposed upwardly into the wedge block to exert uniform upward pressure on the wedge block, and means, supported by said bolster supporting springs, whereby the coil spring is maintained within the wedge block to exert upward pressure.

5. In a railway car truck bolster stabilizer, truck side frames with bolster receiving openings, a spring supported bolster provided'adjacent its ends with transversely arranged pockets open at the sides of the bolster and with openings through the bottom of the bolster communicating with said pockets; hollow wedge blocks and cooperating friction blocks insertible through the open ends of said pockets the friction blocks being disposed at opposite sides of each wedge block and adapted to extend through the sopningsLiirthe-:bolster sides, :theffriction blocks panda' wedge @blocks Jhaving.'f complementary' suraces? whereby the 'friction'. blocks are. simulta- :fneously :caused to moverl laterally outward' into -frictionat engagementwiththe `adjacent portions of. fthe" bolsterz and of .the truck side `frame throughtthe upward pressure of the wedge blocks; #wedge blo'ck'controlling springs adapted tov t s: intcfsaid wedge blocks-to fexert constant YVupward pressure onsaid blocks; andspring holding means 'f'.adapteditoeffect interengaging relation with the lfriction lblocks to preventtdisplacement of said `rinfieansithrough the'fopeningsin the bolster botf tom;;.-said springstandzsprin'g holding means being i insertible. J through' said bottom i'openings :with =.s'aid1holding means adapted `to extend vsubstantially Hush with the -fbolster-bottom and `be sup- .p'ortedz in vplace "by .the bolster loadA` carrying 'irsprings 36.. In a railwaycar truck bolsterstabilizer; the fccombinationof a truck side frame with a bolster yend receiving 'opening and' load 'carrying springs, a bolster .provided lat lthe ends with transversely :disposed pockets .openatfthe sidesfof the bolster fandV having openings through the bottom of. `the abolster; a pair'of friction :members arranged in #each pocket, hollowv wedge'. blocks arranged in- :termediate vthe frictiony blocks; vertically disposedcoil `springs'arranged in said hollow wedge 1 blocks to'iexert constant upward pressure on the wedge blocks; spring `holding means arranged in saldi bolster-bottom :Openingssaid spring 'holdping" means 'and friction blocks having 1ug-andpslotrinterengaging connections for vholding said f means ywith -the'fsuperposed .'springsf in position during assembly,:said. spring holdingmeans being `-heldilus/h1""with .thebolster bottomy by the .load :acarryingrsprings .whenth'e ,bolsterA is` inoperative position.

LrIn a; railroad car"truck.'.bolster stabilizer, the.combination 'of` truck side framesv with h'.bolster endfreceiving openings andload supporting1springs' inlisaid openings, a bolster provided adjacent' the" ends `'.with r transversely'. `disposed straight walled pockets open at the bolster sides and having openings through the bolster bottom at the bolster median line; stabilizing means arranged in said pockets consisting of friction blocks having plane top, bottom, sides and outer end walls and sloping inner ends, wedge mem '.bers with sloping ends matching the sloping inner `ends ofthe friction blocks for forcing the ends of the friction blocks through Vthe open V`ends of the pockets into engagement with the upper wall of the bolster and with the adjacent side frame, verticallyl disposed coil springs varranged in the wedge members for forcing the .latter upwardly and into wedgingrelation with the. friction blocks, spring supporting members for said vertically disposed springs insertiblev in the bolster bottom openings and maintained 4v.flush with the bolster bottom by said bolster supporting springs, and means associated with said friction blocks arranged to have controlling :relation with said spring supporting members Awhereby. the latter are held suspended in the ybolster bottom openings and the wedge membersrelieved of spring pressure when thebolster is. out of contact with said load supporting springs.

8. I n a railway car truck bolster stabilizer, the combination of a truck side frame with a column at'feach side of a bolster-opening, a bolster hav- ;ing an end substantially rectangular in cross #section and arranged in said opening, bolster supporting springs arranged in the'bottom o--said opening, the bolster ends-'being' each tformed with a transversely extending .substantiallyrrectangular pocket open at the Isides "of thefbolster and having a bottom opening at they vertical sides and outer end walls-and adapted to move sides thereof; a vertically-disposed coil spring arranged within said wedge block to-constantly exert upward pressure on` said wedgefblocleso as to move -said wedge-block into frictional-.en-

gagementv with said-friction shoes;and aremovable cuplil e memberior the lowerendof vsaid coilspring -formed lto-seat in said-- bottom central opening inthe bolster andextendflush with. the bolster bottoin,v .saidI cupdilie .member l being adapted to beheld to itsfseat bythe bolster supporting springs.

9. In a railwayucar truck bolster lstabilizer, truck side frames with windowbpenings, .bolster supporting spring means seatedinthe .bottoms of saidopenings, and a .bolster whose ends extend into said windowopeningsand rest on said spring means, the bolster ends vbeing formed with .rectangular straight walled pockets extending transversely and having openings at the bolster sides and with a centralA opening in the bottom, 'bolster stabilizing means arranged entirely within .said pockets, comprising apair .of rectangulariric- .tion shoes in each pocketV at opposite sides of said bottom opening and in slidable contact with rthe top wall. of the pockets, provided with plane outer endsl slidably. engaging non-movable por tions of the truck defining said window openings and having upwardly and inwardly sloping inner ends, a hollow wedge lblockwith=an open bottom between the inner endsof'each'rpair of shoes and having sloping sides matching-.the

inner ends oi the shoes and in constant contact therewith, a vertically disposed coil springvar- Vrangedy in each wedge block in pressingirelation with the upper wall of the wedge block'thereby forcing the shoes into frictional engagement with the side walls of the window openings', and: a supporting member for the lower end of ieach coil spring, seatable in the bottom opening inzthe bolster so as to extend ilush with the bottom and 'to be supported in place by the bolster `supporting springs, whereby the friction' shoes are under constant outwardly forcing pressure, and means whereby the friction shoes may be temporarily held in retracted position during assembly 'fof the bolster in the window openings ofthetruck frame.

10. In a railway car truck provided with load supporting springs, and abolster with plane four walled transverse pockets with openings at the sides and in the bottom noon-resting on said springs, stabilizing means housed in the bolster pockets, comprising, friction shoes with upwardly and inwardly sloping inner faces mounted in opposite sides of said pockets, hollow open bottom wedge members arranged Aentirely within said bolster pockets, positioned between and contacting the angular inner `faces of the shoes,-for

simultaneously Aurging the upper surfaces ofthe Afm.

9 shoes into bolster top contact and their outer ends into frictional contact with non-movable portions of the truck adjacent the outer ends of the shoes, spring supporting members positioned beneath said wedge members in the bolster bottom opening and having upstanding portions disposed above the bolster bottom, vertically disposed coil springs seated on said spring supporting members with their upper ends extending into and maintaining constant upward pressure on said wedge members, the bottom of said spring supporting members being adapted to extend iiush with the bolster spring seat and to be so maintained by the bolster supporting springs, and means movable on the bolster bottom, constituting a part of the stabilizing means, arranged to automatically effect holding relation with said upstanding portions of the spring supporting members to hold the latter in suspended position when said supporting members are free of the load supporting springs.

11. In a car truck, the combination of truck side frames with bolster end receiving openings, wear receiving means; a truck bolster whose ends extend into said frame openings; spring means arranged in said openings for yieldingly supporting the bolster; bolster stabilizing means consisting of a plurality of cooperating movable elements arranged within the bolster ends and involving a pair of friction blocks having flat top and outer side surfaces and inner inwardly sloping surfaces; an upwardly movable hollow wedge member having upwardly and inwardly sloping cuter surfaces complemental to and in constant engagement with the inner surfaces of said blocks and disposed vertically between said blocks; an independent spring arranged vertically in said wedge member in contact with the top wall thereof for constantly urging said wedge member upwardly and maintaining the complemental faces in yielding engagement and thereby causing the friction blocks to exert upward pressure on the bolster and said blocks to move laterally into friction engagement with the wear receiving means of the truck; and a rigid member at the bottom of said independent spring, supported in operative position by the rst mentioned spring means when the bolster is supported by said means, for supporting said independent spring and formed to have interengaging relation with certain of the movable elements of the stabilizing means and thereby hold the rigid member against dissociation with said independent spring when the bolster is out of contact with said i-lrst mentioned spring means.

12. In a railway car truck bolster stabilizer, a truck side frame provided with a bolster end receiving opening and bolster supporting springs, a bolster provided with transversely disposed pockets adjacent the ends open at opposite sides of the bolster and having openings through the bottom; a pair of friction blocks slidably arranged in each pocket and having inner sloping ends and adaptedto contact the top wall of the pocket and the adjacent portions of the truck frame, the friction blocks at their bottoms having extensions disposed inwardly toward each other at opposite sides of the bolster bottom opening; a hollow open bottom wedge block in each pocket intermediate the pair of friction blocks and having sloping surfaces matching and in contact with the sloping surfaces o1 the friction blocks; means whereby the wedge block is held spaced from the bolster bottom to provide passage for the friction block extensions; pressure springs arranged in each wedge block for forcing the latter upwardly and thereby control the wedging relation between the wedge blocks and the friction blocks; a rigid member for supporting the pressurespring and arranged in the bolster bottom opening and formed to effect interengaging holding relation with said friction block extensions whereby said rigid member is held suspended in the bolster bottom opening and the pressure springs permitted to expand out of wedge block pressure condition when the bolster is out of contact with the supporting springs.

13. In a railway car truck bolster stabilizer, a side frame provided with a bolster opening, a bolster having an end portion extending into said bolster opening, said bolster having a transversely disposed pocket open at opposite sides of the bolster and having an opening through the bottom of the bolster, a pair of friction shoes with sloping inner ends slidably arranged in the pocket and adapted to contact adjacent portions of the side frame, the shoes at their inner ends having horizontally extending lugs disposed toward the bottom opening, a wedge member in said pocket intermediate the friction shoes having end sloping surfaces in contact with the sloping inner ends of the friction shoes, a vertically disposed spring arranged under said wedge member moving it upwardly to urge the friction shoes into engagement with the side frame, a rigid member engaging the lower end of said spring arranged in the opening at the bottom of the bolster, said rigid member being formed to effect interengaging relation with the friction shoe lug whereby the rigid member is permitted to drop in the bolster bottom opening and allow said wedge spring to expand out of wedge pressure condition during assembly, and load supporting springs carried by the side frame engaging said bolster end portion and said rigid member maintaining the same in position compressing said spring.

KARL M. HAMLTON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 972,921 Ritter Oct. 18, 1910 2,257,109 Davidson Sept. 31, 1941 2,365,198 Lehrman Dec. 19, 1944 2,392,597 Lehrman Jan. 8, 1946 2,392,599 Light Jan. 8, 1946 A2,422,201 Lehrman June 17, 1947 2,444,011 Lehrman June 22, 1948 

